It would depend on the main lens you are using. I could see the benefits of an upgrade with the long super tele lenses, both in AF speed and IQ. I would include the 70-200mm f/2.8L Mark II in this group as well. The difference of the later is not jumping right at you though but still visible, IMHO. Whether it is worth upgrading or not will be highly subjective and it varies widely obviously.
I have two lenses with which I use the extenders, 70-200 f/2.8L IS II (both 1.4x and 2x used with this lens), and 500 f/4L IS (1.4x only).
I bought the new ones to try them out, before selling the second generation extenders I already had. I found the difference to be significant enough that I kept the third generation extenders, and sold the second generation extenders. I've been quite happy with that decision.
Sometimes it is not easy to understand what is going on with those darn extenders, and what kind of variations one might encounter from one application to another......all I know is that my 300 f/2.8 IS MkI works better with MkIII 1.4xTC and 2xTC, than with the MkIIs ( I am referring to IQ only.)
Also, I have been quite impressed with the MkIII TCs on 70-200 f/2.8 IS MkII as far as IQ is concerned, although I never tried that lens with the MkII extenders.
Lastly, I have found that 1.4xTC MkIII works fairly well with 800L and 500 f/4 MkI, again, talking about IQ.
In all of the above instances, I haven't seen any differences in AF performance between MkII and MkIII extenders.
PetKal wrote:
Sometimes it is not easy to understand what is going on with those darn extenders, and what kind of variations one might encounter from one application to another......all I know is that my 300 f/2.8 IS MkI works better with MkIII 1.4xTC and 2xTC, than with the MkIIs ( I am referring to IQ only.)
Also, I have been quite impressed with the MkIII TCs on 70-200 f/2.8 IS MkII as far as IQ is concerned, although I never tried that lens with the MkII extenders.
Lastly, I have found that 1.4xTC MkIII works fairly well with 800L and 500 f/4 MkI, again, talking about IQ.
In all of the above instances, I haven't seen any differences in AF performance between MkII and MkIII extenders....Show more →
I believe canon white papers still states a 75% decrease in autofocus speed with Mk II and Mk III 2x extenders, though it may hunt less/focus more accurately. So I am not surprised.
kevindar wrote:
I believe canon white papers still states a 75% decrease in autofocus speed with Mk II and Mk III 2x extenders, though it may hunt less/focus more accurately. So I am not surprised.
Yes, if I remember right, Canon wrote about improved precision when MkIII TCs were used with MkII supertelephoto lenses. However, they seem to have left the lens AF drive speed unchanged as with MkII TCs.
RobDickinson wrote:
They are nto slowing down the AF by choice! You have 1/4 of the light you had before, so the AF system works 75% slower..
That is right, I think.
It is very very difficult is to assess the speed of AF with a bare lens, and compare the experience of one user vs. another, because in real world application there is a maddening number of factors and subtleties which affect the perceived performance. Then, you add a TC to the mix, and the issue becomes even more complicated.
I just bought the 2X III after owning the 2X II for the past 4 years or so, used with my 300 f2.8 IS. It's a slight improvement, nothing major. And I knew that going in but had received a $300 gift card for a camera store and that's what I used it for, throwing in the other $200. Each person would have to decide for themselves if it's worth the cost. For some people it's not going to be worth it. If you're going to buy the new versions of the Super telephotos, then by all means get it.
Anyone tried the 2X III on the 135L? I've heard that the 2X II is not really the best with the 135L so I have avoided it. Just wondering if I should maybe reconsider a 2X if the 2X III is significantly better.
RobDickinson wrote:
They are nto slowing down the AF by choice! You have 1/4 of the light you had before, so the AF system works 75% slower..
Mmm . not so sure as long as there is plenty of light. easy way to test is to try the combo with both taped and untaped pins . if the taped pins trys to AF faster then they are slowing it down by choice.
thats not a bad thing though as the time to an AF lock could be quicker with a slower AF speed. its pointless having a fast drive if the AF runs past the point of focus and has to run back.
